Ketogenic diet protects dopaminergic neurons against 6-OHDA
neurotoxicity via up-regulating glutathione in a rat model of
Baohua Chenga,c,⁎,1,Xinxin Yanga,b,1, Liangxiang Anb, Bo Gaoa, Xia Liua, Shuwei Liuc
aJining Medical College, Jining, China
bRizhao People's Hospital, Rizhao, China
cMedical College of Shandong University, Jinan, China
A R T I C L E I N F OA B S T R A C T
Accepted 17 June 2009
Available online 25 June 2009
The high-fat ketogenic diet (KD) leads to an increase of blood ketone bodies (KB) level and
has been used to treat refractory childhood seizures for over 80 years. Recent reports show
that KD, KB and their components (D-beta-hydroxybutyrate, acetoacetate and acetone)
have neuroprotective for acute and chronic neurological disorders. In our present work, we
examined whether KD protected dopaminergic neurons of substantia nigra (SN) against 6-
hydroxydopamine (6-OHDA) neurotoxicity in a rat model of Parkinson's disease (PD) using
Nissl staining and tyrosine hydroxylase (TH) immunohistochemistry. At the same time we
measured dopamine (DA) and its metabolites dihydroxyphenylacetic acid (DOPAC) and
homovanillic acid (HVA) in the striatum. To elucidate the mechanism, we also measured
the level of glutathione (GSH) of striatum. Our data showed that Nissl and TH-positive
neurons increased in rats fed with KD compared to rats with normal diet (ND) after
intrastriatal 6-OHDA injection, so did DA and its metabolite DOPAC. While HVA had not
changed significantly. The change of GSH was significantly similar to DA. We concluded
that KD had neuroprotective against 6-OHDA neurotoxicity and in this period GSH played
an important role.
© 2009 Elsevier B.V. All rights reserved.
Parkinson's disease (PD) is a neurodegenerative disorder
characterized by motor symptoms including tremor, muscle
rigidity, paucity of voluntary movements, and postural
instability (Qu et al., 2007). It is characterized by a progressive
and selective degeneration of dopaminergic neurons of the
substantia nigra (SN) and the exact cause and underlying
mechanism responsible for the progressive neurodegenera-
tion of sporadic PD remains unknown (Chen et al., 2007).
Reduced glutathione (GSH) is a cellular reductant, which
protects against oxidative stress (Leret et al., 2002). Post-
mortem research shows 40% decrease of GSH in SN of PD
patients (Sian et al., 1994). Thus, it has been suggested that
low levels of nigrostriatal GSH contents and consequent
oxidative stress might contribute to the degeneration of
dopaminergic neurons in idiopathic PD (Pinnen et al., 2007).
Although GSH is not the only antioxidant molecule reported
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⁎ Corresponding author. Fax: +86 537 2217079.
E-mail address: firstname.lastname@example.org (B. Cheng).
1These authors contributed equally to these works.
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Imamura, K., et al., 2006. D-beta-hydroxybutyrate protects dopa-
minergic SH-SY5Y cells in a rotenone model of
Parkinson's disease. J. Neurosci. Res. 84, 1376–1384.
Jarrett, S.G., et al., 2008. The ketogenic diet increases
mitochondrial glutathione levels. J. Neurochem. 106,
Koustova, E., et al., 2003. Ketone and pyruvate Ringer's
solutions decrease pulmonary apoptosis in a rat model of
severe hemorrhagic shock and resuscitation. Surgery 134,
Kulich, S.M., et al., 2007. 6-Hydroxydopamine induces
mitochondrial ERK activation. Free Radic. Biol. Med. 43,
Laffel, L., 1999. Ketone bodies: a review of physiology,
pathophysiology and application of monitoring to diabetes.
Diabetes Metab. Res. Rev. 15, 412–426.
Leret, M.L., et al., 2002. Deprenyl protects from MPTP-induced
Parkinson-like syndrome and glutathione oxidation in rat
striatum. Toxicology 170, 165–171.
Maguire-Zeiss, K.A., et al., 2005. Synuclein, dopamine and
oxidative stress: co-conspirators in Parkinson's disease? Brain
Res. Mol. Brain Res. 134, 18–23.
Noh, H.S., et al., 2006. Ketogenic diet protects the hippocampus
from kainic acid toxicity by inhibiting the dissociation of bad
from 14-3-3. J. Neurosci. Res. 84, 1829–1836.
Paxinos, G., Watson, C., 1982. The Rat Brain in Stereotaxic
Coordinates. Academic Press, Sydney.
Pinnen, F., et al., 2007. Synthesis and study of L-dopa-glutathione
codrugs as new anti-Parkinson agents with free radical
scavenging properties. J. Med. Chem. 50, 2506–2515.
Qu, D., et al., 2007. Role of Cdk5-mediated phosphorylation of Prx2
in MPTP toxicity and Parkinson's disease. Neuron 55, 37–52.
Seyfried, T.N., et al., 2003. Role of glucose and ketone bodies in the
metabolic control of experimental brain cancer. Br. J. Cancer 89,
Shimizu, E., et al., 2002. Roles of endogenous glutathione levels on
6-hydroxydopamine-induced apoptotic neuronal cell death in
human neuroblastoma SK-N-SH cells. Neuropharmacology 43,
Sian, J., et al., 1994. Alterations in glutathione levels in Parkinson's
disease and other neurodegenerative disorders affecting basal
ganglia. Ann. Neurol. 36, 348–355.
Smith, S.L., et al., 2005. KTX 0101: a potential metabolic approach
to cytoprotection in major surgery and neurological disorders.
CNS Drug Rev. 11, 113–140.
Sullivan, P.G., et al., 2004. The ketogenic diet increases
mitochondrial uncoupling protein levels and activity. Ann.
Neurol. 55, 576–580.
Tanaka, K., et al., 2002. GPI1046 prevents dopaminergic
dysfunction by activating glutathione system in the mouse
striatum. Neurosci. Lett. 321, 45–48.
Tieu, K., et al., 2003. D-beta-hydroxybutyrate rescues
mitochondrial respiration and mitigates features of Parkinson
disease. J. Clin. Invest. 112, 892–901.
Vanitallie, T.B., et al., 2005. Treatment of Parkinson disease with
diet-induced hyperketonemia: a feasibility study. Neurology
Zhou, C., et al., 2008. Oxidative stress in Parkinson's disease: a
mechanism of pathogenic and therapeutic significance. Ann.
N. Y. Acad. Sci. 1147, 93–104.
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